1. Technical Field
The present invention relates to a circuit device, an electronic apparatus, a moving object, and so on.
2. Related Art
In the past, there has been known a circuit device for outputting a wireless transmission signal in a frequency band such as an RF band. In such a circuit device, there is provided a power amplifier for supplying an antenna with the electric power. As the related art of the power amplifier, there can be cited, for example, technologies disclosed in JP-A-2007-201698 (Document 1), Mona M. Hella and Mohammed Ismail, “RF CMOS Power Amplifiers—Theory, Design and Implementation,” Kluwer Academic Publishers, p. 21, 2002 (Document 2), and so on.
For example, in the related art related to Document 1, there is disclosed a method of performing control so that a voltage applied to an RF choke coil becomes a desired voltage using an operational amplifier to thereby make the output voltage constant independently of a battery terminal voltage.
However, in the past circuit devices for wireless communications, it has not been achievable to realize a power amplifier capable of stably supplying the electric power in a broad power range from high power to low power while suppressing the dependency on a power supply voltage variation or the like.
According to the method of Document 1, it is possible to keep the output power constant by controlling the voltage applied to the choke coil using an operational amplifier. However, as described in Document 1, since it takes much time (time necessary for the output level to be stabilized) to switch the power amplifier from the OFF state to the ON state, there is a problem that it is difficult to increase the transmission rate of the data in, for example, the amplitude modulation using an ON/OFF keying (OOK) method.